UK police on Sunday charged a teenager with violent disorder and assault after an anti-immigrant demonstration at a hotel housing asylum seekers, which saw protesters throw fireworks and set alight a police van.

Merseyside Police said they had charged 19-year-old Jarad Skeete over the beating of an emergency worker, after carrying out 15 arrests over the clashes on Friday evening in Knowsley, near Liverpool.

The clashes broke out when troublemakers came to a planned demonstration by refugee advocacy groups outside the hotel, police said.

They came as the UK is experiencing record numbers of migrants arriving in small boats across the Channel.

Police said Skeete, who comes from a Liverpool suburb, had been remanded in custody and would appear in court Monday, while 14 others were released on conditional bail pending further investigation.

The clashes took place outside a hotel where the far-right group Patriotic Alternative had protested earlier this month, though the group denied it was the organiser.

Police linked the protest to social media and rumours that a man-made "inappropriate advances" to a 15-year-old girl in the area, saying this was used as "an excuse to commit violence".

Interior Minister Suella Braverman condemned the violence, saying on Twitter that the "alleged behaviour of some asylum seekers is never an excuse for violence and intimidation".

Braverman backs a controversial government plan to send asylum seekers arriving via the Channel to Rwanda.

(AFP)